Recovery of Model Pharmaceutical Compounds from Water and Organic Solutions with Alginate-Based Composite Membranes

Abstract

In this work, we combined the non-solvent induced phase separation (NIPS) and further cross-linking by cations towards the preparation of nanofiltration membranes based on sodium alginate, a biodegradable, natural polymer. Acetone, ethanol, toluene, and hexane were used as non-solvents, and cations of calcium, silver, and aluminum—for polymer cross-linking, respectively. Results showed the precipitation strength of non-solvent played a noticeable role in the membrane’s performance; for instance, the toluene permeability changed by four orders of magnitude with the decrease of precipitation strength of the non-solvent: acetone (Ptoluene = 0.1 kg∙m−2∙h−1∙bar−1) < ethanol (3 kg∙m−2∙h−1∙bar−1) < hexane (41 kg∙m−2∙h−1∙bar−1) < toluene (415 kg∙m−2∙h−1∙bar−1). It was shown that simultaneous precipitation and crosslinking in aqueous solutions AlCl3 or AgNO3 must be used in the preparation of alginate membranes for the highly selective recovery of pharmaceutical compounds from organic media. These membranes show rejection R = 90–93% of substances with MW = 626 g/mol and ethanol permeability PEtOH = 1.5–2.5 kg∙m−2∙h−1∙bar−1. For the highly selective recovery of pharmaceutical compounds from water, the method of obtaining membranes must be changed. Precipitation in toluene and then crosslinking in aqueous solutions of AlCl3 or AgNO3 must be used sequentially instead of simultaneous precipitation and crosslinking in aqueous solutions of the same inorganic salts. The permeability of such membranes varied from 0.44 to 7.8 kg∙m−2∙h−1∙bar−1 depending on the crosslinking cation in the alginate. The rejection of model substances with MW 350 and 626 g/mol were on the level of 99%. Alginate membranes can be used to solve separation problems in the pharmaceutical field, for example, to isolate antibiotics from their extractants and remove the same antibiotics from aqueous pharmaceutical waste to prevent their accumulation in the environment and the emergence of resistant genes and bacteria.

Recyclable 3D-Printed Composite Hydrogel Containing Rice Husk Biochar for Organic Contaminants Adsorption in Tap Water

“…In addition, it is possible to note that the intensity of the band at 1460 cm −1 increases because of the higher availability of C−O groups proceeding from the biochar. 39 Together, these findings suggest that RH biochar was incorporated into the Alg matrix.…”

Eco-Friendly OSN Membranes Based on Alginate Salts with Variable Nanofiltration Properties

“…The membrane was placed in the precipitation bath (0.35 mol-eq·L −1 aqueous solutions of inorganic salts) for 30 min. This method of preparingalginate membranes was recognized as optimal based on the results of our previous work [ 26 ].…”

“…Membranes can be made from natural polymers [ 22 , 23 , 24 , 25 , 26 , 27 ]. They can be used as independent membrane materials, as supports for thin selective layers [ 28 ], in mixtures with synthetic polymers [ 29 ], and also in combinations with each other [ 30 ].…”

“…Ref. [ 26 ] wasdevoted to the choice of the optimal method for preparation OSN alginate membranes. It was shown that it is preferable to use crosslinking with aqueous salt solutions without the pre-precipitation with organic solvents.…”

Fabrication, Property and Application of Calcium Alginate Fiber: A Review

“…Based on the ability to gel with metal ions, different alginate-based materials with various morphology were developed, such as the porous scaffold [ 9 , 10 , 11 ], hydrogel [ 12 , 13 ], fiber [ 14 , 15 , 16 ], nonwoven fabric [ 17 , 18 ], membrane [ 19 , 20 , 21 ], and so forth. The common way to fabricate the alginate-based materials includes ion cross-linking [ 22 ], microfluidic spinning technique [ 23 ], freeze-drying [ 24 ], wet spinning technology [ 25 ] and immersive rotary/centrifugal jet spinning technique [ 26 , 27 , 28 ].…”